A suspension is a general title for any transmission force connecting means between a vehicle frame (axle) and wheels, which is intended to transmit a force acting between the wheels and the vehicle frame, and to dampen an impact transferred to the vehicle frame or vehicle body from an uneven road surface, and to attenuate vibrations caused thereby, so as to ensure smooth running of the vehicle.
Early vehicles usually take rigid axle suspensions in which leaf springs serve as elastic elements. Later on, leaf springs were replaced by coil springs, torsion bar springs, air springs, rubber springs, hydro-pneumatic springs and so on. At present, high-level vehicles generally employ independent suspensions, such as transverse arm type, trailing arm type, single oblique arm type, sliding pillar type, Macpherson type, multi-link and active suspension, etc.
A double wishbone independent suspension is a widely used suspension type. The double wishbone independent suspension has a rather small surrounding space, and is staggered with the power shaft, steering rod, balance bar and elastic element within the same space. That is, elastic elements and shock absorbers are suspended from it at a single point vertically. Over the years that the double wishbone independent suspension has been put into application, due to such factors as having too many structural parts, ever-changing environment, frequent change in carrying, continuous work, limited bearing point space, and the like, no modification or innovation has been made thereto.